Production of waxes of improved quality



United States Patent 2,995,508 PRODUCTION OF WAXES 0F IMPROVED QUALITYWeldon G. Annable and John W. Walsh, Crystal Lake, 111., assignors toThe Pure Oil Company, Chicago, 111., a corporation of Ohio No Drawing.Filed July 21, 19 58, Ser. No. 749,660 4 Claimsl (Cl. '208-21) Thisinvention relates to new and useful improvements of paratfin wax blendsand more particularly to a meth- 0d of preparation of improved p araffinwaxes of high tensile strength.

In manufacturing lubricating oils, waxes are obtained as by-products.Parafiin waxes are obtained by the solvent dewaxing of lubricating oildistillates while microcrystalline waxes are obtained from the residuumor still bottoms. Paraflin waxes are generally softer and lower inmelting point than microcrystalline waxes and are less expensive. Toincrease the marketability of paraffin waxes having low tensile strengthproperties, several methods have been heretofore proposed. These methodshave involved the addition of a small proportion of microcrystalline waxto a low tensile strength paraffin wax, as in Adams et a1., U.S. Patent2,127,668, or by distilling a paraffin wax into a number of distillatecuts and blending non-consecutive cuts, as in Bowman et al., U.S. Patent2,467,959.

It is an object of this invention to provide an improved method ofpreparing parafiin wax compositions of relatively high tensile strength.

Another object of this invention is to provide an improved process forpreparing parafiin wax compositions of improved tensile strength whichdoes not require the addition of microcrystalline wax or the use ofnon-consecutive cuts of a fractionated, de-oiled parafi'in wax.

A feature of this invention is the provision of a process for preparingparafiin wax compositions of improved tensile strength by fractionatinga crude oil to produce a heavy lubricating oil distillate, a mediumlubricating oil distillate, and a light lubricating oil distillate,dewaxing each of said distillates, deoiling the waxes, and mixing asmall amount of wax obtained from the heavy distillate with wax obtainedfrom a lighter distillate.

Other objects and features of this invention will become apparent fromtime to time throughout the specification and claims as hereinafterrelated.

In accordance with our invention, a non-asphaltic crude, i.e., aparaflinic or naphthenic crude, or a deasphalted crude, is fractionatedto remove the more volatile fractions (gasoline, naphtha, kerosine, gasoils, etc.) and to produce a heavy lubricating oil distillate, a mediumlubricating oil distillate, a light lubricating oil distillate, and aresiduum. The heavy lubricating oil distillate is de Waxed, by solventdewaxing or by refrigerating and filtering, to produce a high-meltingparafiin wax, M.P. of 140-l60 F. (preferably about 150 F.). From themedium lubricating oil distillate, there is obtained a paraflin waxhaving a melting point of about 136. F., while the wax from the lightlubricating oil distillate has a melting point of about 123 F. When thewax obtained from the light distillate or the medium distillate, or amixture thereof, is blended with a small proportion of the wax obtainedfrom the heavy distillate, a wax blend is produced which has asubstantially improved tensile strength.

The following non-limiting examples are illustrative of the scope ofthis invention.

EXAMPLE I A Van Zandt, Texas, crude oil was distilled to remove the morevolatile components, e.g., gasoline, naphtha,

kerosine, etc., and heavy, medium, and light wax distillates wereobtained. A heavy wax distillate is one having a viscosity of 800-1200S.U.S. at 100 F., and is used in the production of 650 vis. neutral oil.The medium wax distillate is a less viscous oil from which a 200 vis.neutral oil is obtained. The light wax distillate is a still lessviscous oil from which an vis. neutral oil is obtained. The waxdistillates which were thus produced were each subjected to methyl ethylketone-toluene dewaxing and the resulting waxes de-oiled using the samesolvent. The physical properties of the waxes thus obtained are shown inTable I.

Table l Parafiin Wax From 85 Vis 200 Vis 650 Vis Neutral Neutral NeutralMelting Point, F 123.0 136. 8 150. 6

Oil Content, Wt. Percent.-- 0.6 0.2 0.3

Penetration at 77 "F 19 13 21 Tensile Strength, #/sq. in. 308 280Viscosity, SUS, at 210 F- 36 40. 1 51. 2

Gravity at 190 "F 54. 3 63.0 48.5

Distillation, Fz

- I.B.P 717 735 793 732 751 832 734 760 857 738 802 906 742 827 942 751848 981 767 885 1, 037 775 898 1, 053 810 920 1, 066

A small amount of the F. M.P. paraflin wax was added to portions of thelower melting waxes and a very substantial improvement in tensilestrength of the wax blend was observed. For example, when 150 F. M.P.parafiin wax of 276 p.s.i. tensile strength was added to 136 F. M.P.paraflin wax of 308 p.s.i. tensile strength, a series of blends wasobtained having the tensile strengths indicated in Table II. The tensilestrengths of the indi- As is apparent from Table II, the addition ofvery small amounts of 150 F. M.P. wax to a lower melting wax, or mixtureof lower melting waxes, will produce a blend having a tensile strengthhigher than that of any component used in the blend.

We have also found that blends of waxes containing the 150 F. M.P.parafiin wax reach a maximum tensile strength upon addition of 7-11% ofthe higher melting point wax. Beyond this concentration of the highermelting point wax, blends are obtained which have improved tensilestrength but which are of less tensile strength than blends containing711% of the higher melting point wax. These findings are illustrated bythe blends in Table III.

In this series of blends, it is seen that a mixture of 123 F. and 136 F.M.P. waxes has a tensile strength intermediate the individualcomponents. However, the addition of even a small amount of 150 F. M.P.wax, see blend B, produces a wax blend having a tensile strength higherthan any component in the blend. As was pointed out above, the additionof further amounts of 150 ,F. M.P. parafiin causes an increase intensile strength up to a concentration of about 7%. At higher or lowerconcentrations of the 150 F. M.P. paraffin wax, the tensile strength islower. Obviously, the'f'amount of 150 F. M.P. wax required to givemaximum tensile strength will be different for different wax blendsaccording to the relative proportions of the lower melting pointcomponents. The addition of a small amount of the 150. F. M.P. waxproduces a similar improvement in the tensile strength of the 123 F.M.P. wax.. 1 I

As previously set forth, this invention doesnot rely on close-cutfractions of a distilled wax or the addition of microcrystalline waxes,but is predicated on the discovery that high tensile strength wax blendsmay be produced by first fractionating an oil into heavy, medium, andlight wax distillates, dewaxing each of said distillates, de-oil- Whilewe have described this invention with particular emphasis upon apreferred embodiment thereof, we wish it understood that within thescope of the appended claims, this invention may be practiced otherwisethan as specifically described.

This application is a continuation-in-part of our copending application,Serial No. 576,535, filed April 6, 1956, for Production of Waxes ofImproved Quality, now abandoned.

What is claimed is:

1. A high-tensile-strength wax blend consisting essentially of 70 to 99%by weight of waxes of the group consisting of (l) wax having a meltingpoint of about 123 F., a penetration at 77 F. of about 19, and aviscosity at 210 F. of about 36, said wax having been obtained bysolvent dewaxing a petroleum traction to produce -a lubricating oilhaving a viscosity of about 85; and paraffin wax having a melting pointof about 136 F., a penetration at 77 F. of about 13, and a viscosity at210 F. of about 40.1, said wax having been obtained by solvent dewaxinga petroleum to produce a lubricating oil having a viscosity of about 200(2) and mixtures thereof, said blend containing not less than about 35%by weight of paraflin wax (2), and about 1 to by weight of a paraflinwax having a melting point of about 150 F., a peneration at 77 F. ofabout 21, and a viscosity at 210 F. of about 51.2, said wax having beenobtained by sol- I vent dewaxing a petroleum fraction to produce alubricatto 20% by weight.

ing the waxes, and mixing the higher melting point wax (150 F. M.P.)with one or more or the lower melting point waxes.

In carrying out this invention, the waxes which are prepared from theindividual wax distillates arede-oiled to an oil content of not morethan 2% and preferably less than about 0.5 The amount of the highmelting point wax used in the blend may vary between 1 and 30% of theblend, but preferably lies between about 5 and 20% of the blend.

Blends made in accordance with this invention have better color andproduce a higher gloss than blends made with microcrystalline wax, andhave a high melting point and higher tensile strength thanmicrocrystalline wax blends. Additionally, this invention enablesthe useof substantially all the wax from neutral lubricating oil distillate ascontrasted with the necessity of discarding a portion thereof whenfollowing certain prior art procedures.

3. A wax blend in accordance with claim 1 in which the enumerated waxesare present in the amounts of about 52%, about 41%, and about 7%, byweight, respectively.

4. A wax blend in accordance with claim 1 in which said 136 F. meltingpoint wax is present in the amount of about 91% by weight, and said F.melting point wax is present in the amount of about 9% by weight.

References Cited in the file of this patent UNITED STATES PATENTS1,439,171 Kennedy Dec. 19, 1922 2,157,625 Page May 9, 1939 2,658,852Tiedje et a1 Nov. 10, 1953 2,682,523 Talley et a1 -June 29, 19542,758,100 Bailly et alI Aug. 7, 1956 2,761,814 Post Sept. 4, 19562,825,635 Dooley et al. Mar. 4, 1958 2,906,443 Harvey et a1 Sept. 29,1959 2,915,451 B-artay et a1. Dec. 1, 1959 UNITED STATES PATENT OFFICECERTIFICATION OF CORRECTION Patent No.;- 2,995,508 August 8,, 1961Weldon G. Annable et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 4 line 13, before "wax" insert paraffin column 4, line 17, after"85" 's-t'nik e out the semicolon; same line 17, after "and" insert (2)line 22, for 200(2)" read 200; -=v-; line 26, for "peneration" readpenetration (SEAL) Attest:

ESTON G. JOHNSON Attesting Officer DAVID L, LADD Commissioner of Patents

1. A HIGH-TENSILE-STRENGTH WAX BLEND CONSISTING ESSENTIALLY OF 70 TO 99%BY WEIGHT OF WAXES OF THE GROUP CONSISTING OF (1) WAX HAVING A MELTINGPOINT OF ABOUT 123* F., A PENETRATION AT 77*F., OF ABOUT 19, AND AVISCOSITY AT 210*F. OF ABOUT 36, SAID WAX HAVING BEEN OBTAINED BYSOLVENT DEWAXING A PETROLEUM FRACTION TO PRODUCE A LUBRICATING OILHAVING A VISCOSITY OF ABOUT 85; AND PARAFFIN WAX HAVING A MELTING POINTOF ABOUT 136*F., A PENETRATION AT 77*F, OF ABOUT 13, AND A VISCOSITY AT210* F. OF ABOUT 40.1, SAID WAX HAVING BEEN OBTAINED BY SOLVENT DEWAXINGA PETROLEUM TO PRODUCE A LUBRICATING OIL HAVING A VISCOSITY OF ABOUT 200(2) AND MIXTURES THEREOF, SAID BLEND CONTAINING NOT LESS THAN ABOUT 35%BY WEIGHT OF PARAFFIN WAX (2), AND ABOUT 1 TO 30% BY WEIGHT OF APARAFFIN WAX HAVING A MELTING POINT OF ABOUT 150*F., A PENETRATION AT77*F., OF ABOUT 21, AND A VISCOSITY ST 210* F. OF ABOUT 51.2, SAID WAXHAVING BEEN OBTAINED BY SOLVENT DEWAXING A PETROLEUM FRACTION TO PRODUCEA LUBRICATING OIL HAVING A VISCOSITY OF ABOUT 650, EACH SAID WAX HAVINGAN OIL CONTENT OF LESS THAN ABOUT 0.5%.